Change in vdsm[master]: Fix block volume atomicity creation issue. - vdsm-patches - Fedora mailing-lists

20 Nov 2012

Hello Ayal Baron, Haim Ateya,
I'd like you to do a code review.  Please visit
http://gerrit.ovirt.org/9358
to review the following change.
Change subject: Fix block volume atomicity creation issue.
......................................................................
Fix block volume atomicity creation issue.
BlockVolume creation is a 2 step process where first an LV is
created and then tags are added to it. If another host refreshes
it's cache between the 2 commands it will have an LV with partial
data on it. To solve this issue, we add an initial tag to the
lvcreate command so that any other host would be able to identify
this volume as incomplete and ignore it.
Special LVs still have not MD tags.
Bug-uri: https://bugzilla.redhat.com/show_bug.cgi?id=876558
Change-Id: I40cd67e563935de663d938cbc1bc9cf152802448
Signed-off-by: Eduardo ewarszaw@redhat.com
Reviewed-on: https://gerrit.eng.lab.tlv.redhat.com/3299
Reviewed-by: Ayal Baron abaron@redhat.com
Tested-by: Haim Ateya hateya@redhat.com
---
M vdsm/storage/blockVolume.py
1 file changed, 29 insertions(+), 14 deletions(-)
git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/58/9358/1

diff --git a/vdsm/storage/blockVolume.py b/vdsm/storage/blockVolume.py
index 98c471b..692f8cd 100644
--- a/vdsm/storage/blockVolume.py
+++ b/vdsm/storage/blockVolume.py
@@ -20,6 +20,7 @@
import os
 import threading
+import logging
 import sanlock
from vdsm.config import config
@@ -42,6 +43,7 @@
 TAG_PREFIX_MDNUMBLKS = "MS_"
 TAG_PREFIX_IMAGE = "IU_"
 TAG_PREFIX_PARENT = "PU_"
+TAG_VOL_UNINIT = "RHAT_VOL_INITIALIZING"
 VOLUME_TAGS = [TAG_PREFIX_PARENT,
                TAG_PREFIX_IMAGE,
                TAG_PREFIX_MD,
@@ -58,6 +60,7 @@
 #  - 2..100  (Unassigned)
 RESERVED_LEASES = 100
+log = logging.getLogger('Storage.Volume')
 rmanager = rm.ResourceManager.getInstance()
@@ -159,7 +162,8 @@
         else:
             volSize = "%s" % (size / 2 / 1024)
-        lvm.createLV(dom.sdUUID, volUUID, volSize, activate=True)
+        lvm.createLV(dom.sdUUID, volUUID, volSize, activate=True,
+                                                initialTag=TAG_VOL_UNINIT)
fileUtils.safeUnlink(volPath)
         os.symlink(lvm.lvPath(dom.sdUUID, volUUID), volPath)
@@ -180,11 +184,11 @@
with cls._tagCreateLock:
             mdSlot = dom.mapMetaOffset(volUUID, VOLUME_MDNUMBLKS)
-            lvm.addLVTags(dom.sdUUID, volUUID, (
-                            "%s%s" % (TAG_PREFIX_MD, mdSlot),
-                            "%s%s" % (TAG_PREFIX_PARENT, srcVolUUID,),
-                            "%s%s" % (TAG_PREFIX_IMAGE, imgUUID,)
-            ))
+            mdTags = ["%s%s" % (TAG_PREFIX_MD, mdSlot),
+                      "%s%s" % (TAG_PREFIX_PARENT, srcVolUUID),
+                      "%s%s" % (TAG_PREFIX_IMAGE, imgUUID)]
+            lvm.changeLVTags(dom.sdUUID, volUUID, delTags=[TAG_VOL_UNINIT],
+                         addTags=mdTags)
try:
             lvm.deactivateLVs(dom.sdUUID, volUUID)
@@ -541,13 +545,15 @@
     def getMetaOffset(self):
         if self.metaoff:
             return self.metaoff
-        l = lvm.getLV(self.sdUUID, self.volUUID).tags
-        for t in l:
-            if t.startswith(TAG_PREFIX_MD):
-                return int(t[3:])
-        self.log.error("missing offset tag on volume %s", self.volUUID)
-        raise se.VolumeMetadataReadError("missing offset tag on volume %s"
-                                          % self.volUUID)
+        try:
+            md = _getVolumeTag(self.sdUUID, self.volUUID, TAG_PREFIX_MD)
+        except se.MissingTagOnLogicalVolume:
+            self.log.error("missing offset tag on volume %s/%s",
+                            self.sdUUID, self.volUUID, exc_info=True)
+            raise se.VolumeMetadataReadError("missing offset tag on volume"
+                                        "%s/%s" % (self.sdUUID, self.volUUID))
+        else:
+            return int(md)
def getMetadataId(self):
         """
@@ -633,7 +639,16 @@
def _getVolumeTag(sdUUID, volUUID, tagPrefix):
-    for tag in lvm.getLV(sdUUID, volUUID).tags:
+    tags = lvm.getLV(sdUUID, volUUID).tags
+    if TAG_VOL_UNINIT in tags:
+        log.warning("Reloading unfinished volume %s/%s", sdUUID, volUUID)
+        lvm.invalidateVG(sdUUID)
+        tags = lvm.getLV(sdUUID, volUUID).tags
+        if TAG_VOL_UNINIT in tags:
+            log.error("Unfinished volume %s/%s", sdUUID, volUUID)
+            raise se.VolumeDoesNotExist("%s/%s" % (sdUUID, volUUID))
+
+    for tag in tags:
         if tag.startswith(tagPrefix):
             return tag[len(tagPrefix):]
--
To view, visit http://gerrit.ovirt.org/9358
To unsubscribe, visit http://gerrit.ovirt.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I40cd67e563935de663d938cbc1bc9cf152802448
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Eduardo ewarszaw@redhat.com
Gerrit-Reviewer: Ayal Baron abaron@redhat.com
Gerrit-Reviewer: Haim Ateya hateya@redhat.com

    